As the oil pump having the configuration described above, Patent Document 1 discloses an oil pump having an inner rotor 3 configured to be driven-rotated, and an outer rotor 4 which is configured to engage with outer teeth of the inner rotor 3 and disposed at an eccentric position to the inner rotor 3. The outer rotor 4 is rotatably supported on an inner periphery of a cam ring 5, and the cam ring 5 is supported by a support pin 10 swingably in a radial direction and at the same time movably in a direction to a center of an internal circle. A biasing force of a spring 7 is allowed to act on the cam ring 5 so that a volume of a transported oil pooling portion 11 of a suction region 21 becomes the maximum.
By the action of the biasing force of the spring 7, a control pressure chamber 20 is formed between the cam ring 5 and a pump body 1, and an oil pressure of a discharge outlet 17 is allowed to act on the control pressure chamber 20. When the pressure in the discharge outlet 17 is increased, the cam ring 5 is swingably moved in the radial direction by the pressure, and by this swingable movement, a position of a rotation center of the outer rotor 4 is allowed to revolve with a tooth height of an internal gear pump as a revolution diameter.
Also in Patent Document 1, by the revolution of the outer rotor 4, the volume of the transported oil pooling portion 11 is allowed to change which is formed by the outer teeth of the inner rotor 3 and the inner teeth of the outer rotor 4 on a terminal vicinity 22 of the suction region 21 of the pump body 1, and as a consequence, the adjustment of the discharge amount is realized.
As another oil pump having the configuration described above, Patent Document 2 discloses an oil pump in which an inner rotor 3 and an outer rotor 4 are eccentrically arranged, and a ring gear actuation set 5 is disposed therebetween. The outer rotor 4 is rotatably supported on an inner periphery of an adjustment ring 14, and an outer teeth line 24 is formed in an outer periphery of the adjustment ring 14. An inner teeth line 24′ is formed in an inner periphery of a casing portion 1 or a press-cut ring 27, and the inner teeth line 24′ and the outer teeth line 24 are eccentrically arranged.
In the casing portion 1, a rocker lever configured to actuate the adjustment ring 14 is swingably supported, and by swinging the rocker lever, a rotational axis of the outer rotor 4 is moved at an angle of 90 degrees to an opposite side in the inner rotor 3, while the inner teeth line 24′ and the outer teeth line 24 are engaged with each other. With this movement, a positional relationship of the ring gear set 5 of the inner rotor 3 and the outer rotor 4 relative to a low-pressure port 8 and a high-pressure port 9 is changed, and the discharge amount of the pump can be adjusted between the maximum and zero.
Patent Document 1: Japanese Unexamined Patent Application Publication No. 8-159046 (paragraphs [0012]-[0028] and FIGS. 1-4)
Patent Document 2: Japanese Unexamined Patent Application Publication No. 10-169571 (paragraphs [0030]-[0046] and FIGS. 1-3)